Why Does My Dog... Vomit Yellow Foam?

In most cases, yellow foam indicates that the dog's stomach is relatively empty of food. The yellow color comes from bile, a digestive fluid that's produced in the liver, stored in the gall bladder and then released into the small intestine just below the stomach.

A dog may vomit yellow foam simply because his stomach is empty and the bile can be irritating. If your dog is otherwise healthy — and he's eating and defecating normally — it may help to reduce the time in between meals. But this doesn’t mean that your dog should be fed more. Instead, one meal can be divided into two or three smaller but more frequent feedings.

Unfortunately, there are many medical conditions that can cause a dog to vomit on an empty stomach, so a phone call to your vet is a good idea if you notice this problem.

Potential Medical Concerns

If there’s something in the vomit besides yellow foam, it may help to bring a sample to your veterinarian. Of course, if there’s grass in the foam, for example, you may already have your answer. So keep your dog from grazing on the lawn, and see if the vomiting subsides.

If your dog shows other signs, including loss of appetite, lethargy and diarrhea — or if you notice a yellow tinge to your dog’s skin, eyes or gums — it merits a trip to your veterinarian. The problem may be as simple as a sudden diet change, stress or side effects from medication. But it could also be something more serious, such as pancreatitis, toxins, liver disease, parasites, allergies and more. When a foreign body is involved, like that sock that suddenly went missing, it may even require emergency surgery.